End caps for containers

ABSTRACT

A container having a tubular central section forming sides and rigid end caps in positive engagement. The sides have perforations near the rims and the rigid end caps have engaging means consisting of a first portion for insertion in said perforations and a second portion for preventing the disengagement of said perforations from said first portion.

United States Patent [191 Vajtay [451 Oct. 21, 1975 1 END CAPS FOR CONTAINERS 21 Appl. No: 340,400

[52] US. Cl 220/4 R; 220/67, 220/315 [51] Int. Cl. B65D 7/00 [58] Field of Search 220/4 R, 4 F, 60 R, 42 F, 220/42 A, 67, 315

[56] References Cited UNITED STATES PATENTS 1,157,041 10/1915 Reynolds 220/60 R 2,504,850 4/1950 Lermer 220/60 R 2,606,586 8/1952 Hill 220/42 F 2,801,039 7/1957 Arneson.... 220/60 R 2,837,236 6/1958 Betner 220/60 R 2,969,160 1/1961 Delk, Jr. 220/60 R 2,984,382 5/1961 Florsheim, .11. 220/60 R 3,161,345 12/1964 McLeod 220/60 R 3,223,278 12/1965 Allen 220/60 R 3,424,341 1/1969 Slapnik 220/60 R 3,692,204 9/1972 Provi et a1. 220/4 F Primary Examiner-William 1. Price Assistant Examiner-Steven M. Pollard Attorney, Agent, or FirmTheodore E. Galanthay [57] ABSTRACT A container having a tubular central section forming sides and rigid end caps in positive engagement. The sides have perforations near the rims and the rigid end caps have engaging means consisting of a first portion for insertion in said perforations and a second portion for preventing the disengagement of said perforations from said first portion.

19 Claims, 9 Drawing Figures US. Patent Oct.21, 1975 SheetlofZ 3,913,774

FIG. 3A

FIG. 4

US. Patent 0a. 21, 1975 Sheet 2 of2 3,913,774

| l 1 l i END CAPS FOR CONTAINERS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to containers having tubular central sections and rigid end caps therefor, and more particularly to means for positively engaging the end caps and central sections to each other.

2. Description of the Prior Art It is known in the packaging art to fabricate containers having tubular central sections and rigid end caps. The tubular central section may be given any desired cross-sectional shape such as an ellipse, circle, or polygon, and is then reinforced in the desired shape by the rigid end caps. The tubular central sections forming relatively flexible sides are normally a thermo-plastic material approximately 0.005 to 0.050 inches in thickness and manufactured to form a tube. Various techniques have been employed in the joining of rigid end caps to the flexible sides including the use of adhesives, tape, staples and other fastening materials. Another known technique is to provide an end cap structure for frictionally engaging the thin flexible sides. In most applications, however, frictional engagement is inadequate and a positive engagement is required. There is no known prior art technique suitable for providing a container of the type disclosed herein that is either permanently closed or easily reopenable. Moreover, prior art manufacturing techniques do not lend themselves to a one-step assembly by either hand or machine, for providing a positive engagement between flexible sides and rigid end caps.

SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide an improved end cap for a container with a tubular central section.

It is another object of this invention to provide an improved container having flexible sides and at least one rigid end cap.

It is still another object of this invention to provide an improved engaging means for interlocking flexible sides with rigid end caps.

It is a further object to provide an improved method of fabricating a package.

In accordance with the present invention, a flexible thermo-plastic material is utilized as the tubular central section for the sides of a container. This material can be sheets of poly-vinyl chloride (p.v.c.), oriented polystyrene (o.p.s.) or any other flexible, semi-rigid sheet material. The sheets may be pre-extruded, extruded or calendared to a thickness of approximately 0.005 to 0.050 inches, and adhesively joined along a longitudinal seam, forming tubes. The sheets or tubes may also be creased along a predetermined number of edges, to form a container with a polygon cross-section, such as a rectangle, for example. The resultant creased tubular member is then cut into desired lengths, depending on the size of the container to be fabricated. Perforations are punched near the rims for interlocking with the end caps. The tubular central section may also be extruded directly over a mandrel or injection molded. Also, materials other than plastics, such as metal, paper, cardboard and others may be used so long as they fulfill the functional requirement of relative flexibility. By flexible herein is meant a semi-rigid self sustaining material sufficiently thin to be temporarily deformed by the engaging means described. Thus, a relatively less flexible and/or thicker material requires a wider spacing of the opposed camming surfaces of the engaging means, for an interlock of comparable permanence.

The end caps are formed from a plastic material, usually by molding, and resultin rigid end members providing strength to the entire container. The dimensions and shape of the end caps conform to the dimensions and shape of the flexible sides. The end caps have a base portion, and flange portions, substantially forming the end covers for the container. The end caps also have engaging means for interlocking with the perforations in the flexible sides thereby providing a positive lock for holding the container together. The engaging means essentially consists of first and second portions, for opposed camming surfaces, the first portion being a wedge shaped protrusion deforming the flexible side until the wedge shaped protrusion latches in the perforation at which time the flexible side snaps back into its original shape. The second portion of the engaging means cooperates in the camming action with the first portion until the wedge shaped protrusion latches in the perforation at which time it becomes essentially a retaining surface to prevent the disengagement of the perforation from the wedge shaped protrusion. This retaining surface may either by a single continuous surface or a plurality of separate surfaces such as a pair of straddling pins or members on either side of the wedge shaped protrusion. By the term retaining surface is meant any obstruction in proximity to the wedge shaped protrusion and adapted to cooperate with the wedge shaped protrusion such that the perforated side and wedge shaped protrusion do not readily disengage. As will be explained later herein, the first and second portions of the engaging means may be positioned and dimensioned to cooperate with each other to provide a permanent package that is disassemblable only by special tools or destruction of the container material. The degree of rigidity and thickness of the flexible sides also affects the desired spacing of the opposed camming surfaces.

The package of the present invention is uniquely assemblable by either hand or machine because the end cap locks to the tubular central section without the need for adhesives, tapes, staples, or any other fastening material and without a secondary operation. During the assembly process, the perforations and engaging means are virtually self-aligning, completing the package when the engaging means interlocks with the perforations.

The above mentioned objects, features and advantages of the invention, together with others inherent in the same, are attained by the embodiments illustrated in the drawings, the same being merely preferred exemplary forms, and are described more particularly as follows.

IN THE DRAWINGS FIG. 1 is an exploded perspective view of a container in accordance with the present invention.

FIG. 2 is an exploded perspective view of an alternate embodiment of a container in accordance with the present invention.

FIG. 3 is a section on line 3-3 of FIG. 1.

FIG. 3A is a vertical cross-section of FIG. 3 taken along line 3A3A.

FIG. 4 is a broken perspective view of an end cap specifically showing an engaging means in accordance with the present invention.

FIG. Sis a top view of an alternate embodiment of an end cap in accordance with the present invention.

FIG. SA is a side view of an end cap along section line SA-SA in FIG. 5.

FIG. 6 is an alternate embodiment of an engaging means in accordance with the present invention.

FIG. 7 is another alternate embodiment of an engaging means inaccordance with the present invention.

Refer now to FIG. 1 for an exploded perspective view of the container in accordance with the present invention. The container has, a tubular, central section 10 forming a plurality of flexible sides 12 and rigid end caps and 22. Flexible sides 12 are normally produced in the form of a tube from a thin flexible sheet of thermo-plastic material having a preferred thickness of approximately 0.005 to 0.050 inches. Of course, relatively large packages require eorrspondingly thicker material. The tube may be given any desired crosssectional shape such as the rectangle illustrated in FIG. 1. The tubes 10 are cut to a desired length, substantially the desired heightof the container, and perforations 14 are made near the rims, as shown. The highest degree of precision is obtained by perforating and cutting the tube in the same fixture or during the same operation, after the tube has been formed. These perforations 14 are positively engaged by the engaging means which are integral with end caps 20 and 22. At least one perforation 14 is required to engage at least one engaging means in an end cap to interlock the end cap with the flexible sides. If the tubes are formed and creased flat for the perforating operation, then perforations are made in pairs. If one of such a pair of perforations is extraneous, the package is still satisfactory. The perforations 14 are shown approximately half way between the edges of the flexible sides for purposes of illustration. It is possible to place them elsewhere so long as they are in registration with the engaging means in the end cap. In the case of a large container, several perforations and engaging means may be desired along each side of the container. Perforations can even be made at the corners.

Refer now to FIG. 2 showing a container having a non-polygonal cross-sectional area. It is noted that a circle is a special case for an ellipse so that an elliptical cross-section is equally illustrated by the FIG. 2 em bodiment. In FIG. 2 flexible side 12 of tubular central section 10 has perforations placed as in the FIG. 1 embodiment. Again, the number of perforations and corresponding engaging means in end caps 20' and 22" is determined primarily by the circumference of the cross-sectional area and the desired strength of the resultant package. The FIG. 2 embodiment shows that the present invention has application in containers having flexible tubular central sections of any crosssectional area whether polygonal or non-polygonal. Also, the flexible tubular central section, i.e., flexible sides 12 or 12 need only be flexible near the end caps to engage the end caps in accordance with the present invention.

Refer now to FIG. 3 for a cross-sectional viewktaken along line 33 in F161, illustrating end cap20 in greater detail. End cap 20 has a base-portion 24 and a plurality of axially extending rigid flanges such as 25 and 26. In embodiments utilizing a circular or elliptical trated in FIGS. 3 and 3A should be substantially equal cross-section, flanges 25 and 26may be considereda single flange. Flange 25 has an inner surface 25' and an outer surface 25". Flange 26 has an inner surface 26 and an outer surface 26". The flanges 25 and 26 are integral with base portion 24. and extend upwardly substantially perpendicular to the periphery of the base portion. The engaging means also shown in FIG. 3 are I each comprised of a first portion such as protrusion 30 and a second portion such as a retaining surface illustrated by straddling pins ormembers 32.Protrusions 30 are integral with the flanges and'extend from the flanges in proximity to and adapted to cooperate" with the retaining surface. The retaining surface is shown integral with the base portion extending upwardly from the base portion in proximity to the flange and the protrusion 30.The first and second portions of the engaging means thus form opposed camming surfaces that may be interdigitated camming surfaces depending on their dimensions. A section along line 3A3A in FIG.

3 is shown in FIG. 3A to more particularly illustrate the cooperation of the protrusion 30 and the retaining surface illustrated by reference numerals 32' and 32", for example. Protrusion 30 is wedge shaped and has a look ing surface 30' extending substantially perpendicularly from the flange and a guiding surface 30 extending from the outer most extention of the locking surface to the flange. The retaining surface provided by straddling members 32 is integral. with the base portion 24 and spaced from the flange in accordance with the thick-.

ness of the flexible side 12 to be held in proximity to the flange. Each of the straddling members 32 include a holding surface 32 and a guiding surface 32"; .the

holding surface extending upwardly from the periphery of the base portion, the guiding surface extending from 1 the outer most extension of the holding surface away from the flange and forming an obtuse angle with the holding surface. Thus, when a thin flexible member such as a flexible side 12 is slid along, the inner surface of the flange, then the flexible member is deformed by i to the dimension B illustrated in FIG. 1. Also, the engaging portion of the perforated edge should be parallel with the rim. In this manner, the portion of the flexible member between the perforation and the rim of the flexible member is approximately equal to the distance between the locking surface 30' and the contacted portion of base portion 24. It is noted that in this position of locking engagement, the retaining surface provided by straddling members 32 prevents the disengagement of perforation 14 from protrusion 30. Note also that the distance C which is the spacing between the retaining surface and the flange is in accordance with the thickness of the flexible side to be heldin proximity to the flange. Assuming that the flexible sides 12 are formed by adhesively joining along a longitudinal seam, then it is frequently desired to have an area of overlap. This p overlapping adhesively joined section will have a thickness approximately twice that of the thin flexible side 12. Assuming that the flexible sides 12 of the container are approximately 0.010 inches thick, then the overlap portions will be approximately 0.020 inches thick and this latter dimension should be approximately equal to the dimension C. As further shown in FIG. 3, dimension D is the distance between straddling members 32. To increase the permanence of the engagement between a rigid end cap and a flexible side, the straddling members are brought closer together lessening dimension D, thereby tightening the space between the protrusion 30 and the straddling members. A similarly increased permanence is attained by widening protrusion 30. Similarly, if the height of a straddling member including surfaces 32 and 32" is raised, then the opposed surfaces 32 and 30" become inter-digitated increasing the permanence of the package. Note that surfaces 32 and 32" have been shown as such for ease of illustration, but actually form a single continuous surface. In addition to the foregoing, FIG. 3 shows a raised portion 34 parallel with at least portions of the flanges and spaced from the flanges in accordance with the thickness of the flexible side to be held in proximity to the flange.

This raised portion 34 is further illustrated in FIG. 4 which also shows a perspective view of the presently discussed embodiment of the engaging means. Corresponding features in FIG. 4 have been numberedwith reference numerals corresponding to those in previous figures insofar as practical. Note base portion 24 integral with at least one upwardly extending flange 25 having inner surface 25' and outer surface 25". Note also that it would be possible instead of an entire flange 25 to have merely a flange portion sufficient to support the engaging means the flexible side 12. FIG. 4 further illustrates the retaining surface exemplified by straddling members 32 integral with base portion 24 and extending upwardly in proximity to the flange portion. Also illustrated in FIG. 4 is the wedge shaped protrusion 30 integral with flange 25 and extending from the inner surface 25 substantially between the straddling pins 32. Protrusion 30 has a locking surface 30' and a guiding surface 30", A suitable angle between guiding surface 30" and the vertical surface 25' is approximateiy 30". In FIG. 4, the protrusion 30 and straddling members 32 are dimensioned to be interdigitated forming interdigitated opposed camming surfaces.

Refer now to FIG. 5 which shows an alternate em-, bodiment of a rigid end cap having four flanges 25, 26, 27 and 28. Refer also to FIG. 5A which is a section of FIG. 5 along line 55. The end cap is comprised of base portion 24' and flanges 25 and 26, etc., as in the previous example. The engaging means again comprises a wedge shaped protrusion and a retaining surface forming interdigitated opposed camming surfaces. In this embodiment, however, the retaining surface is provided by a single continuous surface as opposed to a pair of straddling members 32. The retaining surface 35 might be a portion of raised portion 34 previously described. The function of the retaining surface 35 is to form an opposed camming surface with protrusion 30 and to retain the flexible sides 12 in their locked position. The present embodiment also shows a raised platform 37 which is included as part of the base portion, the raised platform being in a plane inwardly from the periphery of the base portion. This raised platform may further be used to advantageously mount items to be displayed in the container. Note that it is possible to construct all portions of the presently described container from not only transparent materials,

but also anydesired color for attractiveness and sales appeal.

Refer now to FIG. 6 again showing a portion of an end cap with emphasis on the locking means. The end cap comprises base portion 24 integral with at least one upwardly extending flange portion 25. FIG. 6 particularly shows that the two portions of the engaging means may be reversed. Thus, as shown in FIG. 6, the wedge shaped protrusion 30 is integral with the base portion while the retaining surface 35 is integral with the flange portion.

FIG. 7 further illustrates that it is possible to provide the wedge shaped protrusion 30 with a convex guiding surface 30". This facilitates the moving of perforation 14 into registration with protrusion 30, particularly in nonpolygonal configurations. It is similarly possible to round or otherwise adapt the retaining surface (s) as desired.

What has then been described is an improved container and end cap therefor that is both permanently or temporarily assembled by a single manual or machine operation. The tubular central section is perforated and cut into desired lengths forming flexible sides for a container. Rigid end caps having substantially rigid engaging means in registration with the perforations are provided. The end caps are shaped so as to be readily moldable as a rigid plastic material. The flexible sides are slid into the end caps deforming the flexible sides until the engaging means interlocks with the perforations.

While several examples illustrative of preferred embodiments have been described, those skilled in the art will recognize that various changes in the disclosed structures and exemplary methods may be made without departing from the spirit and scope of the invention.

What is claimed is:

l. A container having a tubular central section forming a plurality of sides and at least one rigid end cap, said at least one end cap positively engaging at least one of said plurality of sides, the combination comprisat least one perforation insaid at least one of said plurality of sides; said rigid end cap'having a base and a plurality of rigid flanges of the same number as said plurality of sides, said-flanges being contiguous with at least a portion of said sides; and

at least one substantially rigid engaging means integral with said rigid end cap, said engaging means having at least two fixedly spaced apart portions, a first portion forming a first camming surface for flexing said at least one of said plurality of sides in a first direction and also forming a protrusion engaging said at least one perforation, said second portion forming an opposed camming surface for flexing said at least one side in an opposite direction and also forming a retaining surface integral with said rigid end cap for preventing the disengagement of said perforation from said protrusion.

2. A container as in claim 1 wherein the protrusion is wedge shaped and comprises:

a locking surface extending substantially perpendicularly from the flange; and

a guiding surface extending from the outer most extension of said locking surface tothe flange.

1 3..A container as in claim 2 wherein the guiding surface is convex.

. 4. A container as in claim 1 in which said retaining a surface includes a pair of straddling members each comprising:

a. holding surface integral with the base portion and v spaced from the flange in accordance with the g thickness of the side to be held in proximity to the 5. A container as in claim 4 wherein said pair of straddling members each further include;

a gu iding surface extending from the outer most extension of said holding surface away from said f flange.

6. A containeras in claim 1 in which said base portion includes:

' a raisedportion forming a surface substantially parallel with at least portions of said flanges, and spaced from said flanges in accordance with the thickness of the side to be held in proximity to the flange.

7; A container as in claim 1 in which said base portion includes:

' 'a raised platform, said raised platform being in a plane inwardly from the periphery of said base portion and forming a plug for the container. 8". An end cap for a flexible sided container comprismg:

' a base integral with at least one upwardly extending flange having inner and outer surfaces; and engaging means integral with said end cap and having at least two fixedly spaced apart, portions, said first and second portions forming opposed camming surfaces; said engaging means being relatively rigid such that when a thin flexible member forming a side and having a perforation is inserted between said first and second portions, then said flexible member is flexed in a first direction by the camming action of said first portion, while being flexed in the opposite direction by the camming action of said second portion until the first portion is inserted in said per- I foration, thereby permitting said flexible member polygonal.

13. An end cap as in claim 12-wherein said base iscir-- extending from a surface of said at least one flange, in proximity to and adapted to cooperate with said retaining surface; such that when a thin flexible member forming a side and having a perforation, is slid alongthe surface of said at least one flange,,then said flexible member is deformed by the cooperation of said protrusion and said retaining surface until the protrusion i is inserted in said perforation, thereby permitting said flexible member to become contiguous with at least some of said at least one flange and locked in place by said protrusion.

l6. An end cap as in claim 15 wherein said protrusion has rounded edges shaped for facilitating the sliding of a thin flexible member,having a perforation, along the length of said flange.

17. An end cap as in claim 15 wherein said protrusion extends inwardly from the inner surface of said atleast one flange.

18.-An end cap as in claim 15 wherein the positions of the retaining surface and protrusion are reversed such that the protrusion becomes integral with the base. i

and the retaining surface becomes integral with the flange.

19.An end cap for covering at least one open end of a container having a tubular central section, comprising:

a base portion, forming a cover for the container, integral with a plurality of axially extending rigid flange portions with an inner surface having sub-. stantially the same crosssection as the outer surface of said tubular central section; and

engaging meansintegral with said end cap and having first and second portions forming opposed cam ming surfaces;

such that when said tubular central section having a perforation is inserted between said first and second portions, then said tubular centralsection, is deformed until the first portion isinserted in said' perforation, thereby interlocking said said tubular central section.

end cap and 

1. A container having a tubular central section forming a plurality of sides and at least one rigid end cap, said at least one end cap positively engaging at least one of said plurality of sides, the combination comprising: at least one perforation in said at least one of said plurality of sides; said rigid end cap having a base and a plurality of rigid flanges of the same number as said plurality of sides, said flanges being contiguous with at least a portion of said sides; and at least one substantially rigid engaging means integral with said rigid end cap, said engaging means having at least two fixedly spaced apart portions, a first portion forming a first camming surface for flexing said at least one of said plurality of sides in a first direction and also forming a protrusion engaging said at least one perforation, said second portion forming an opposed camming surface for flexing said at least one side in an opposite direction and also forming a retaining surface integral with said rigid end cap for preventing the disengagement of said perforation from said protrusion.
 2. A container as in claim 1 wherein the protrusion is wedge shaped and comprises: a locking surface extending substantially perpendicularly from the flange; and a guiding surface extending from the outer most extension of said locking surface to the flange.
 3. A container as in claim 2 wherein the guiding surface is convex.
 4. A container as in claim 1 in which said retaining surface includes a pair of straddling members each comprising: a holding surface integral with the base portion and spaced from the flange in accordance with the thickness of the side to be held in proximity to the flange.
 5. A container as in claim 4 wherein said pair of straddling members each further include: a guiding surface extending from the outer most extension of said holding surface away from said flange.
 6. A container as in claim 1 in which said base portion includes: a raised portion forming a surface substantially parallel with at least portions of said flanges, and spaced from said flanges in accordance with the thickness of the side to be held in proximity to the flange.
 7. A container as in claim 1 in which said base portion includes: a raised platform, said raised platform being in a plane inwardly from the periphery of said base portion and forming a plug for the container.
 8. An end cap for a flexible sided container comprising: a base integral with at least one upwardly extending flange having inner and outer surfaces; and engaging means integral with said end cap and having at least two fixedly spaced apart portions, said first and second portions forming opposed camming surfaces; said engaging means being relatively rigid such that when a thin flexible member forming a side and having a perforation is inserted between said first and second portions, then said flexible member is flexed in a first direction by the camming action of said first portion, while being flexed in the opposite direction by the camming action of said second portion until the first portion is inserted in said perforation, thereby permitting said flexible member to become at least partially contiguous with said at least one flange and locked in place by said engaging means.
 9. An end cap as in claim 8 wherein said base is polygonal.
 10. An end cap as in claim 9 wherein said base is rectangular.
 11. An end cap as in claim 9 wherein the number of flanges equals the number of sides to said polygon.
 12. An end cap as in claim 8 wherein said base is non-polygonal.
 13. An end cap as in claim 12 wherein said base is circular.
 14. An end cap as in claim 13 wherein said at least one flange forms a complete wall.
 15. An end cap as in claim 8 wherein said engaging means comprises: a retaining surface integral with said base portion and extending upwardly in proximity to said flange; a protrusion integral with said at least one flange and extending from a surface of said at least one flange, in proximity to and adapted to cooperate with said retaining surface; such that when a thin flexible member forming a side and having a perforation, is slid along the surface of said at least one flange, then said flexible member is deformed by the cooperation of said protrusion and said retaining surface until the protrusion is inserted in said perforation, thereby permitting said flexible member to become contiguous with at least some of said at least one flange and locked in place by said protrusion.
 16. An end cap as in claim 15 wherein said protrusion has rounded edges shaped for facilitating the sliding of a thin flexible member, having a perforation, along the length of said flange.
 17. An end cap as in claim 15 wherein said protrusion extends inwardly from the inner surface of said at least one flange.
 18. An end cap as in claim 15 wherein the positions of the retaining surface and protrusion are reversed such that the protrusion becomes integral with the base and the retaining surface becomes integral with the flange.
 19. An end cap for covering at least one open end of a container having a tubular central section, comprising: a base portion, forming a cover for the container, integral with a plurality of axially extending rigid flange portions with an inner surface having substantially the same crosssection as the outer surface of said tubular central section; and engaging means integral with said end cap and having first and second portions forming opposed camming surfaces; such that when said tubular central section having a perforation is inserted between said first and second portions, then said tubular central section is deformed until the first portion is inserted in said perforation, thereby interlocking said end cap and said tubular central section. 